JP5964748B2 - Fiber composite material and manufacturing method thereof - Google Patents

Description

  The present application relates to equipment and methods for graphite resin composite members, such as sports racket frames, golf club shafts, and bicycle frames.

  This application claims priority from Chinese Patent Application No. 200910040320.9 filed in China on June 18, 2009 and US Provisional Patent Application No. 61-285051 filed on December 9, 2009. is there. These disclosures are incorporated herein by reference.

  Since ancient times, graphite composite sports racquet frames have been manufactured by a manual method with a mold using air injection. In a typical process, a plurality of sheets, usually made of a fibrous material, such as carbon or graphite fibers, or glass fibers, are manually wrapped or laminated (in the form of flat material strips). ), A “layup” is formed, and an air bag is formed. The air bag is formed using, for example, a number of “sheets” of graphite fibers, and the “sheet” is impregnated with, for example, an uncured thermoplastic or thermosetting resin, for example, in a saturated state. In general, the sheet is manually wound around a rigid core or rod and controlled to the desired layup shape. This is usually a tubular shape.

  Before the graphite is wound around the core, the core is covered with a layer of material, thereby forming the inner surface of an inflated layup bladder during the manufacturing process as described below. The sheet is made of carbon fiber and impregnated with uncured plastic resin as described above. These carbon fiber / resin sheets are manually cut into strips or ribbons before being assembled into a layup and are usually wound around a core to form a tube. After winding, the lay-up (after winding it will be in the form of an air bag) is manually shaped into the desired racket shape and reinforced with an additional patch of carbon fiber flat strip impregnated with resin material And installed in the mold. The resin material can be any material that can be used for graphite or glass fiber composites, and the fibers are bonded together to form a substantially rigid structure.

  Thereafter, the mold is manually sealed. The air bag is heated by the molding and the thermoplastic resin is cured. The final racket is a lay-up hard material. Alternatively, a thermosetting resin may be used.

  The bladder is then inflated by a single air nozzle, placed manually. The nozzles are individually attached to one end of the bladder. The nozzle is supplied, for example, to an air pump that generates compressed air, and the wall of the layup is pressed against the inner wall of the mold hole. See Hsu US Pat. No. 4,511,523 (1985). Since both ends of the layup are configured in an open state, the end of the layup opposite the end inflated by the nozzle is coupled to, for example, a cap or other sealing structure or other technical structure, and the layup Pressure builds up. Thereafter, the mold is heated to cure the thermoplastic resin.

The problem with this process is that the composite racquet frame is typically a single tube configuration. The two ends of the layup tube are at the bottom of the racket, for example in the case of a tennis racket. In other words, the tube starts at the base of the tennis racquet handle and extends substantially linearly along the entire length of the tennis racquet handle and extends around the oval gut support frame. Continue to the initial position of the tube in a direction that returns substantially linearly towards the section. Normally, the base of the handle is cut at the end with a saw,
A set of grip members secured around the end of the tube defines a tennis racket handle. Due to the requirement of air injection, the tubular basic shape requires air to flow through the entire tube. This means that with the technique described above, the direct product must be hollowed out and have an open end shaft at the bottom or base of the tennis racket handle.

  Although it is possible in principle to form a multi-tube composite structure, any change in the arrangement of these tubes due to changes in the air pressure of the bladder and the lay-up characteristics along the entire length of the lay-up Internal areas, bridges, or lumens have also been found difficult to control placement. Past attempts have found significant quality control and manufacturing problems.

  On the other hand, due to the hollow nature of graphite rackets, for example, the tennis racket hoop or head must have a minimum cross-sectional width to allow the tennis racket to withstand strong strokes in normal games. It becomes. For example, in a professional tennis player, the ball speed when serving reaches 150mph.

  On the other hand, a thin frame is preferable in order to enhance swing speed, head speed, controllability, and feeling. In the quality of the material constituting the racket frame manufactured by using the current air pressure processing method, a minimum width of about 19 mm is usually the limit as a hollow frame to be obtained.

  Apart from the strength of the material that makes up the tennis racket, the present invention allows the hollow nature of the existing graphite racket to be vibrated and impacted, especially at off-center positions, compared to the early generation of dense wooden rackets. It is considered that the shoulder and elbow disorders tend to increase in the shots. This is because the open end shaft at the hollow frame and handle is coupled to the hand and even the arm during play.

  In the present invention, it is believed that the air jet opening at the bottom of the shaft exacerbates the impact resonating at the racket handle, which leads to propagation to the player's hands, arms and shoulders.

  Previous industry developments have focused on minimizing these propagating vibration and shock problems by implementing various methods to reduce the transmission of vibrations from the racket handle to the player's hand. .

  The present invention provides a carbon composite frame structure with increased strength and reliability, and by providing a frame head and handle with an inner core of foamed plastic, and if necessary, at the base of the racket handle. Address these issues by providing a secure closed end.

  In the present invention, it is believed that the closure of the end of the racket provides a further improvement in the characteristics of the sports racket.

  Compared to the graphite racquet, the dense wooden racquet absorbed the impact, so that the previous generation wooden racquet did not suffer as much damage to the shoulders and arms as the hollow graphite racquet. In the present invention, the era of air-injected graphite in the manufacture of racquets has generated a fairly high arm and shoulder failure rate not only with conventional hollow graphite racquet technology but also with the open end shaft at the end of the handle. It is thought.

  Further, in the conventional hollow racket, since energy from “misfit” is supplied to the hollow frame, vibrations and impacts related to non-center shots tend to propagate in particular. On the other hand, the dense frame of the present invention suppresses this impact and widens the size of the “sweet spot” on the frame. This is because the energy of the non-center shot does not propagate sufficiently through the frame of the present invention. In the present invention, a combination of thin and dense rackets creates a large “sweet spot” and attenuates the propagation of impact. The result is a surprising increase in the “acceptability” of non-center shots.

  The implementation of sports racquets with a foam core is not known. Cecka U.S. Pat. No. 4,129,634 (1978) discloses the use of foamed plastic material to form an internal filler member in the core of a sports racquet head. However, in the field of graphite racket manufacturing, among the inventors, for many years, a substantial industrial example of such foaming technology within the critical structure surrounding the head of the racket that supports the gut. Has not been seen.

  In the present invention, graphite is pressurized and molded using a foam type material. However, the use of foam is not sufficient with graphite pressing and molding alone. For example, the curing temperature of the carbon resin is usually in the range of 130 ° C. The blowing agent must be of a type that does not substantially expand before reaching the temperature required for curing, for example, up to six layers of carbon fiber. Similarly, it is believed that the expansion needs to be relatively quick. This is because slow expansion causes fiber pitting within the frame structure during curing in the mold.

  In addition, when the lamination pressure of the layers is insufficient, satisfactory characteristics cannot be obtained for the racket. Similarly, if the foam material density is sufficiently high, even if the expansion rate has reached the required level, it does not meet the weight reduction goals for a particular carbon fiber product. In the case of Expancell 152, the expansion coefficient of the foamed plastic forming material used in the present invention is considered to be about 60: 1. It has not been confirmed to produce a racket of sufficient strength in a dense foam material having an expansion ratio in the range of about 2: 1. A jelly-like foam material with an expansion ratio in the range of about 10: 1 also does not reach the ideal, although a measurement improvement is observed. Surprisingly, the microencapsulated foamed plastic material exhibits good strength in the final product and has excellent use properties. This is probably due to the combination of cellular plastic structure and applied pressure.

  The implementation of the present invention may be changed according to the specification of a specific application. In some applications, this is an acceptable weight (eg, some tennis rackets are made for players who prefer heavier rackets), while in other applications, less strength is required but less carbon Cost competitiveness using fiber (for example, badminton rackets have few critical applications).

  Also, in the present invention, it has been found that molding is difficult when the expansion temperature is extremely high. If the expansion rate is not too great, this can adversely affect the strength of the carbon fiber member due to pitching.

  Thus, when forming a sports racket frame using foamed plastic material (pressing carbon fiber and resin layup during formation and suppressing vibration after formation), a wide range of conditions using a wide range of materials Below, a racket frame that can be used for competition is obtained, and according to the above-mentioned parameters, a racket having excellent characteristics is obtained.

  For several years, the use of air pressure nozzles has become an industry practice in the manufacture of graphite rackets. The air nozzle must be manually installed and this process cannot be fully mechanized due to inconsistencies in adapting the air nozzle.

  In the present invention, the process of manufacturing the racquet uses a microencapsulated plastic material containing a foaming agent in the form of a powdered material to form a foamed plastic. This material is placed in a tubular layup bladder and the ends of the bladder are sealed. The air bag is then placed in an iron mold and then heated. As a result, the material is heated and melts and expands under the pressure of the blowing agent contained therein.

  Since no air is jetted from the nozzles, no workers are required to make this connection, and the manufacturing process is substantially unified, saving time. This aspect of the invention provides the possibility of mass production of racket frames, for example in a fully automated process.

  Note that in the present invention, the foaming of the plastic that forms the foamed plastic inner core of the racquet occurs approximately at the temperature required to melt and cure the carbon fiber / thermoplastic sheet layer that forms the layup bladder. There is a need to. However, somewhat higher temperatures are acceptable. The specific temperature is a function of the material used in constructing the foam plastic and may be obtained by daily similar trials and end product variability checks when the temperature is not excessive.

  In the present invention, the layup is filled with a powdered microencapsulated foamed plastic material, which in the example shown below does not expand until the temperature reaches 120-130 ° C, for example 130 ° C. At the same time, due to the foaming action of the microencapsulated material in the bladder, the gas generation pressure in the layup bladder sealed at both ends is increased. Thereby, the fiber layer which forms the racket frame of a final product state is laminated | stacked, and this is pressed on the inner surface of a mold so that the shape of the hole of a mold may be exhibited.

  It is understood that upon application of heat, the microencapsulated blowing agent expands and the capsule covering it deforms, forming a foamed plastic under pressure. As a result, sufficient pressure is generated, the graphite carbon fiber layer is pressed against the mold wall, and the carbon fibers are formed into the shape of the mold holes. As a result of the combination of heat and pressure, the layers melt and form a composite material that constitutes the racket frame. This occurs at a temperature of about 120-130 ° C. You may change this temperature range according to the characteristic of the thermoplastic material which comprises a carbon fiber sheet.

  In a preferred embodiment, the temperature at which the microcapsules expand to form a foamed plastic with the blowing agent is about 130-135 ° C. However, good results can be obtained at temperatures above that level. Similarly, lower temperatures may be used if the thermoplastic resin in the sheet incorporating the carbon fibers has a sufficiently low softening point.

  The foamed plastic formed when the powdered microencapsulated foamed plastic material is heated substantially retains its volume and does not shrink when cooled. After cooling, the plastic material is solidified into a shape inside the mold holes.

  In the method of the present invention using a foamed plastic material, upon heating, a foamed plastic is formed which expands when the plastic material incorporated in the graphite fiber approaches or exceeds the temperature at which it is cured and melted. It was found to be. This eliminates the need for manual work during installation of the air nozzle (and associated problems and resulting non-uniformity problems) and provides a superior strength to weight ratio in composite glass fiber materials.

  Therefore, in the method of the present invention, it is possible to form a racket frame having the same strength (for example, a cross section) wider than that of the conventional frame, and problems relating to the manufacturing method using the air pressure supplied from the nozzle. It can be solved.

  It should be noted that similar equivalent techniques may be used with the present invention. For example, the microencapsulated foaming agent may be placed in a collapsible shell and mixed with a powdered plastic that melts before the microcapsule disintegrates and the foaming agent is released. Alternatively, the microcapsules may only melt themselves at the desired temperature and fuse with the particles of plastic powder. By using various combinations of plastic and microcapsules, various plastic properties such as strength, flexibility, damping, weight rigidity, compressibility, and density can be obtained. For example, rubbery materials may be combined with microcapsules to increase shock and vibration absorption. Alternatively, a rubber-like material may be used as the microcapsule.

  Alternatively, the manufacturing method may include elongated plastic particles. This may be selected for rigidity and may have the property of not melting during pressure generation in the foaming process for the purpose of using multiple layers of carbon fibers. The rubbery material optionally included in the manufacturing process absorbs shock and vibration, and the desired stiffness may be provided by elongated plastic particles.

  In yet another aspect, oriented elongated particles may be incorporated. For example, elongated electret particles that do not melt or lose polarity at the temperature required to form a graphite racquet may be placed in a mixture of microcapsules. This is oriented by an electric field while maintaining a molten state, which results in an orientation that specifically meets the requirements for strength, attenuation, etc. For example, a bicycle frame may be formed using this technique. In this case, application of correspondingly oriented electric fields to different parts of the frame results in different orientations of the particle electrets, which can cope with stresses formed in these parts of the frame during use.

  Conventional tennis rackets include various grip sizes, grip shapes, weights, balances, and swing weight configurations. Rackets with different configurations are usually adjusted at the manufacturing level. This is because consumer changes are difficult in this area. As a result, the store needs to carry a large assortment of various types of tennis rackets. This means that the distribution system is inefficient and there is an extra cost in the supply process. The modular aspect of the racket of the present invention can be easily customized to various configurations and can address this current product problem.

  The resin-fiber composite of the present invention may have an outer shell that defines a hole. The outer shell has a plurality of fiber layers. The first resin material is disposed between the fibers and fixes the fibers to each other. The second resin is disposed inside the hole, and the second resin material is configured and dimensioned to define a void in the hole between the portions of the second resin material. Contained within the void is a gaseous material that is greater than 20 psi under pressure, more preferably 30 pounds per square inch, and most preferably greater than 40 psi.

  A blowing agent is disposed in the hole. The blowing agent and the second resin material are adapted not to react during solidification, and a resin structure arranged and dimensioned to define voids in the holes between the portions of the second resin material. It is formed.

  The resin and fiber layup of the present invention has multiple layers of fibers configured as a sealed air bag, which defines an internal hole in the air bag. A number of first resin materials are placed between the fibers and are adapted to fix and cure the fibers together. The second resin material is disposed inside the hole. The blowing agent is disposed inside the hole. The blowing agent and the second resin material are adapted to be unreactive during placement and dimensioning to form a resin structure, and voids are formed in the holes between the portions of the second resin material. The The void may be a closed cell void or an open cell void.

  The fibers may be in the layer in two different orientations. A layer of air-impermeable material may be disposed in a hole provided between the second resin material and the plurality of layers of fibers.

The hole may be a sealed hole. The gaseous material may be at a pressure exceeding 5 kg / cm ² . For example, it may be greater than 20 pounds per square inch, preferably greater than 30 psi, most preferably greater than 40 or 50 psi, or, in the following examples, the main frame of a tennis racquet containing 25 g Expancell 152. It may be the same level as the pressure formed in connection with up. For many applications, excellent results are obtained at pressures in the range of 5-15 kg / cm ² .

  The one or both ends of the sleeve around which the layup is wound may be configured as a knot or a weave.

  The resin material placed between the fibers may be adapted to be cured by heat. The second resin material may be adapted to be cured by heat. The second resin material may surround the foaming agent.

  The second resin material surrounds the foaming agent, and expansion may occur at substantially the same temperature as the temperature at which the first resin material is cured.

  The second resin material and the foaming agent may be in a powder form instead of a rigid form.

  The second resin material and the blowing agent may have an expansion ratio greater than 30, and the expansion ratio is preferably in the range of about 50-70, for example 60.

  The method for producing a fiber composite member of the present invention includes a step of forming a flat member of fibers impregnated with a resin material, and a step of winding the flat member around a core. A foamed plastic forming material is disposed in the wound flat member. Thereafter, the end portion of the wound flat member is substantially sealed to form a substantially sealed air bag. Thereafter, the sealed air bag is placed in the mold, and the foamed plastic is formed by the foamed plastic forming material. Next, the resin material is cured by heat, for example.

  The cured layup is removed from the mold. Or a mold turns into a member which forms the permanent part of some fiber composite members.

  The core is preferably covered with a sleeve before being wound with the fiber layer. The sleeve may be firmly fixed around the core using an adhesive. The core may be a core having two parts.

  The fiber may be a graphite fiber. The foamed plastic forming material may form the foamed plastic when exposed to a temperature sufficiently close to the temperature at which the resin material is cured by application of heat. In this case, the foamed plastic applies a pressing force to the fiber layer during the curing of the resin material.

  Accordingly, it is an object of the present invention to provide a method for manufacturing a racket frame composed of a composite material. In the present invention, gas injection is not required for expansion of the composite material to form the racket frame, and the frame can be completely surrounded by a hermetic mold during the manufacturing process.

  Another object of the present invention is to provide a method of manufacturing a racket frame having the strength required for play under the conditions required for competition, while remaining within the lower limit of the allowable racket weight range. . This means that the single racket of the present invention can be substantially modified within the player's weight and distribution preferences. In the present invention, this is achieved by introducing an object that is attached to the frame, for example by introducing a weight inside the frame, even after the frame has been manufactured, for example after gutting the frame. be able to.

  A weight can be attached to each position of the frame. These positions may be selected to optimize the characteristics of the racket during play. This is compared to conventional rackets that often require a graphite / polymer composite weight around the head to support the gut. In addition, the structure with weights attached to the conventional manufacturing process, if they are intended, as long as the possibility of the air passage being blocked increases during the manufacturing in the conventional air flow path manufacturing method. Provides complexity.

  Another object of the present invention is to provide a very thin dense racket frame. This racket frame is less impact than conventional hollow frames and has enhanced characteristics due to swing speed and head speed and also has a large hit zone or “sweet spot”.

  Another object of the present invention is to provide a modular racket that is fully customized by the original consumer in the field.

  This method greatly increases the rigidity and strength of the graphite, and makes it possible to perform stronger strokes and shots during sports. It is also expected that the formation of a sealed dense product will reduce the impact and vibrations that lead to tennis elbow and shoulder obstructions. In the present invention, the opposite end of the tube is sealed so that such a structure is obtained. Optionally, the entire tube may be placed in a completely sealed mold. This uses a nozzle and cup that protrudes from the mold, which requires additional manual work to fit the nozzle and cup, and cutting the base of the frame handle after the resin is cured, before curing the resin. This is compared with the conventional manufacturing method.

  Another object of the present invention is to provide a method of forming a graphite fiber member and a manufacturing operation having a single curing step to produce various shapes of graphite fiber elements that are not achieved by conventional pneumatic forming methods. It is. In particular, this is significant because in the shape of the part being manufactured, it is not necessary to provide a continuous path of air flow. Instead, many dishes are assembled and the assembled bladders are combined in the desired configuration and heated and cured.

  Another object of the present invention is to provide a method for producing a graphite fiber composite member without an internal nylon air bag, depending on the viscosity of the foamed plastic, to prevent air leakage through the carbon fiber / resin layup. That is.

  Another object of the present invention is to provide a method that solves the problem of insufficient racket characteristics due to non-uniformities and other problems associated with the nozzle air injection process.

  Another object of the present invention is to use a machine to produce a graphite racquet that minimizes or eliminates human effort.

  Another object of the present invention is to provide a framework for manufacturing composite fiber resin rackets. This allows the weight to be easily placed and the weight and balance of the racket to be adjusted.

  Another object of the present invention is to mold a racket frame having holes. In this case, the need for drilling after the manufacture of the frame is eliminated. This combines two half-racquet layups, one of the half-racquet layups is placed in the bottom half of the mold, and multiple pins placed in the part where the holes are located are placed in the slots provided in the mold Then, the other half racket layup may then be placed over the first half racket layup and the mold sealed with the other half of the mold.

  In one embodiment of the present invention, the racquet is used in a closed racquet handle base structure for the purpose of reducing shock and vibration disturbances as compared to racquets with current graphite racquet open end shafts.

  The operation of the present invention will become apparent from the following description with reference to the accompanying drawings.

It is the figure which showed the conventional graphite tennis racket. 1 is a cross-sectional view of a tennis racquet using unencapsulated rigid foamed plastic in a conventional attempt to use a blowing agent for the production of carbon graphite racquets as described in US Pat. No. 4,129,634 to Cecka. It is the figure which showed the implementation method spread in the industry which comprises the main part of a graphite racket flame | frame using the air injection of the US Patent 4511523 which forms the graphite racket by Hsu. It is the figure which showed the implementation method spread in the industry which comprises the main part of a graphite racket flame | frame using the air injection of the US Patent 4511523 which forms the graphite racket by Hsu. It is the figure which showed the implementation method spread in the industry which comprises the main part of a graphite racket flame | frame using the air injection of the US Patent 4511523 which forms the graphite racket by Hsu. It is the figure which showed the structure of the layup useful for implementation of this invention. 1 is a perspective view of a sealed cellophane tube containing a machined microencapsulated blowing agent. FIG. It is the figure which showed the structure of the layup useful for implementation of this invention. FIG. 7 shows a sealed tubular shell made of cellophane tube containing a microencapsulated foaming agent in cell 152. The tube is covered with a sealed multilayered sheet of resin impregnated fibers. In the present invention, the tube is formed by machine rather than human effort. FIG. 3 illustrates the curing of a tennis racket using a foamed plastic-forming composite material containing microcapsules containing a foaming agent sold under the trademark EXPAN-CELL152 used in the present invention. A fiber tube shaped for the formation of a racket that can be placed in a mold by a machine. FIG. 3 illustrates the curing of a tennis racket using a foamed plastic-forming composite material containing microcapsules containing a foaming agent sold under the trademark EXPAN-CELL152 used in the present invention. FIG. 9 is a horizontal cross-sectional view through the frame head of FIG. 8 showing Expancell 152 in the fiber tube. State before thermoforming (before heat application, before physical softening and expansion of microencapsulated blowing agent). FIG. 9 is a horizontal cross-sectional view through the frame head of FIG. 8 showing Expancell 152 in the fiber tube as compared to pre-thermoforming. State after thermoforming (heat is then applied, the microcapsule expands, the foaming agent operates, the foaming agent expands, and the carbon fibers are pressed against the inner wall of the racquet forming mold). It is sectional drawing of another Example of this invention. The microencapsulated graphite tube after thermoforming is placed in a fiber tube for tube formation within the tube. It is sectional drawing of another Example of this invention. Shown are two tubes formed prior to winding on a second tube. This tube forms a gut support hoop portion or head portion of the tennis racket. It is a figure which shows the shaping | molding method of the handle | steering-wheel part of a racket. It is sectional drawing of the pipe | tube in a pipe structure. It is a figure at the time of manufacturing a frame head. It is the figure which showed the structure of the badminton racket. It is the figure which showed another Example of this invention regarding the racket weight distribution. It is the figure which showed another Example of this invention regarding the racket weight distribution. 2 is an exploded plan view showing a completed customized racket 14. FIG. It is the figure which showed the manufacturing method of the carbon fiber patch used for manufacture of the flame | frame of this invention, and utilized for implementation of the method of this invention. It is the figure which showed the manufacturing method of the carbon fiber patch used for manufacture of the flame | frame of this invention, and utilized for implementation of the method of this invention. It is the figure which showed the manufacturing method of the carbon fiber patch used for manufacture of the flame | frame of this invention, and utilized for implementation of the method of this invention. It is the figure which showed the manufacturing method of the carbon fiber patch used for manufacture of the flame | frame of this invention, and utilized for implementation of the method of this invention. It is the figure which showed the manufacturing method of the carbon fiber patch used for manufacture of the flame | frame of this invention, and utilized for implementation of the method of this invention. It is the figure which showed the manufacturing method of the carbon fiber patch used for manufacture of the flame | frame of this invention, and utilized for implementation of the method of this invention. It is the figure which showed the manufacturing method of the carbon fiber patch used for manufacture of the flame | frame of this invention, and utilized for implementation of the method of this invention. It is the figure which showed the manufacturing method of the carbon fiber patch used for manufacture of the flame | frame of this invention, and utilized for implementation of the method of this invention. It is a block diagram of the graphite assembly used in the case of winding up the layup of a badminton racket. It is a block diagram of the graphite assembly used in the case of winding up the layup of a badminton racket. FIG. 2 shows a two-part core for winding the layup of the present invention. It is the figure which showed the coating | cover of the badminton racket of this invention. It is the figure which showed the coating | cover of the badminton racket of this invention. It is the figure which showed the coating | cover of the badminton racket of this invention. It is the figure which showed the coating | cover of the badminton racket of this invention. It is the figure which showed the coating | cover of the badminton racket of this invention. It is the figure which showed the coating | cover of the badminton racket of this invention. It is the figure which showed the coating | cover of the badminton racket of this invention. It is the figure which showed the coating | cover of the badminton racket of this invention. FIG. 6 shows a tool for filling a layup with microcapsules. It is the figure which showed the wooden mold for forming a badminton racket head. It is the figure which showed another coating | cover of the badminton racket of this invention. It is the figure which showed another coating | cover of the badminton racket of this invention. It is the figure which showed another coating | cover of the badminton racket of this invention. It is the figure which showed another coating | cover of the badminton racket of this invention. It is the figure which showed another coating | cover of the badminton racket of this invention. It is the figure which showed another coating | cover of the badminton racket of this invention. It is the figure which showed another coating | cover of the badminton racket of this invention. It is the figure which showed another coating | cover of the badminton racket of this invention. It is the figure which showed another coating | cover of the badminton racket of this invention. It is the figure which showed another coating | cover of the badminton racket of this invention. It is the figure which showed another coating | cover of the badminton racket of this invention. It is the figure which showed the mold for hardening of the badminton racket of this invention. It is the figure which showed the part of the tennis racket of this invention. It is the figure which showed the structure of the layup of the tennis racket of this invention. It is the figure which showed the structure of the layup of the tennis racket of this invention. It is the figure which showed the structure of the layup of the tennis racket of this invention. It is the figure which showed another thermosetting mold for the handle | steering-wheel formation of the tennis racket of this invention. It is the figure which showed another thermosetting mold for the handle | steering-wheel formation of the tennis racket of this invention. It is the figure which showed completion of formation of the layup of the tennis racket of this invention. It is the figure which showed completion of formation of the layup of the tennis racket of this invention. It is the figure which showed completion of formation of the layup of the tennis racket of this invention. It is the figure which showed completion of formation of the layup of the tennis racket of this invention. It is the figure which showed the thermosetting mold in the time of completion of formation of the layup of the tennis racket of this invention.

  FIG. 1 shows a conventional graphite racket frame 11 having a universal racket shape. Processing using air-blown graphite manufacturing technology has the advantage that the strength to weight ratio exceeds previous wooden rackets. The racket frame 11 has a head portion 12, a throat portion 13, a handle or shaft portion 14, and a grip 15 disposed on the handle 14. These parts of the racket frame 11 are formed as a single, integrated continuous member. The bifurcated throat portion 13 is continuous with the head portion 12 and the shaft portion 14. On both sides of the throat 13, a crosspiece part or a yoke part 16 is provided. The yoke portion 16 and the head portion 12 form a substantially elliptical gut extension portion 17 that surrounds the ball hit surface 18. A concave gut groove 19 is formed on the outer surface of the head portion 12.

  FIG. 2 shows a conventional tennis racket frame structure described in US Pat. No. 4,129,634 to Cecka. Here, the frame 11 ′ has an outer surface formed by a layer of graphite fibers 20 and an inner foam core 22. This product is constructed by winding multiple layers of carbon fiber around a central putty core. Usually, the core includes cork, a resin (such as a thermosetting resin), and a filler material such as a blowing agent that promotes foaming of the resin, and further includes an accelerator and a curing agent. During manufacture, the racquet layup is placed in a tool iron mold and heated. During the formation of the foam core, the pressure generated by the blowing agent provides a pressure that forms the outer shape of the layup and, after cooling, is adapted to the shape of the mold. As mentioned above, this technique appears not to be used in the industry due to undesirable racket characteristics. This is because simple encapsulation of the foamed plastic core does not provide improved play characteristics as found in the present invention.

  In the present invention, the expansion of the foamed plastic occurs substantially simultaneously with or after the softening of the plastic. Thereby, the foam core of the racket of the present invention is formed. Prior to curing, the resin impregnated in the graphite fibers is an adhesive softening material. Thus, if the timing of expansion is not carefully adjusted, the same will occur before curing, followed by curing, and possibly loss of pressure.

  In the present invention, the foam core may have a foam plastic of an open cell or a closed cell. The material used in the preferred embodiment is Expancell®, which has the advantage of being a liquid during the formation of the foamed plastic. In addition, closed cell foam provides a more significant advantage in that it quickly fills the leak at the time of the leak and is more effective in preventing air leakage and pressure loss due to its viscosity to air. To do.

The curing temperature of the carbon resin may be 130 ° C., for example. Pressing the carbon layers against the mold, before the resin is cured, for joining the sheets carbon fiber resin layer to each other, the internal pressure used at 130 ° C. is at least about 7 kg / cm ² (about 100 psi) 15 kg / cm ² (about 215 psi), but in some applications about 5 kg / cm ² can also be used. The selected foamed plastic preferably reaches this pressure during curing. This is most easily obtained when the resin exceeds its curing temperature and then foaming is initiated and cooled before pressure loss occurs.

  Also, many foam expansions are two to three times in size, and at this size, fibers are cut off outside the desired mold shape. The cutting of the graphite fiber yarn damages the configuration and impairs the configuration and strength.

  It should be noted that even if expansion does not occur at the appropriate time, the racket appears to be in the proper state. The adhesion between the graphite layers and the adhesion between the foam core and the graphite layer can be good. However, the adhesion between the graphite layers may not be sufficient to select excellent and / or long life characteristics in the racket frame. Therefore, it is important to apply a sufficiently high pressure in the preparatory stage of foaming and cooling after the resin is polymerized. Of course, if polymerization occurs at a sufficient level, such a pressure can also be formed prior to polymerization.

  If pressure loss occurs after polymerization, it is clear that this is not a serious problem. This is because even if pressure is applied to the graphite layer and the graphite layers are firmly bonded to each other and the thermoplastic frame is in a soft state, the pressure loss does not affect the frame properties of the cooled product. .

  Also, the use of powdered foam plastic material, such as encapsulated foam, allows the graphite to be clipped within the mold by laying up flat when the mold is sealed before the resin-saturated carbon fiber is heat cured. It should be noted that is prevented. When the expansion is slow, fiber pitting is formed outside the mold holes.

  Since the lamination pressure becomes insufficient and the expansion rate of the low carbon fiber becomes high, it is not preferable to use a foam type material that pressurizes and molds graphite. If the foam material density is too high, the lightness required for carbon fiber reinforced products is lost, even if the expansion rate is at the required level.

  3 to 5 show a universal pneumatic racket manufactured with current manufacturing technology. The carbon fibers used to make the layup take the form of a graphite sheet. The graphite sheet is wound around a seamless sleeve to produce a layup.

  Air pressure is applied through the expansion assembly 31. As shown in FIG. 3, the expansion assembly 31 has a valve 30 coupled by a nozzle 32 for receiving a pneumatic source. The expansion assembly 31 has one end coupled to the compressed air source and the other end coupled to the sleeve tube of the layup 33. A layup 33 composed of an inner tubular member and a layer of resin-impregnated graphite material is provided with holes 59 for heat curing the layup defined by mold halves 61, 62 of mold 60 under the application of air pressure. A frame that is placed, molded and cured is formed. See Figure 4.

  A pre-processed soft carbon tube layup 33 composed of carbon fiber and uncured resin is placed in a hole 59 defined by the steel mold halves 61, 62 of the mold 60 when the clamshell is sealed. . The air nozzle 31 is coupled to a compressed air source by a female nozzle coupling 32, which is sealed by a matching male nozzle.

  The completed layup is placed in the bottom mold section 61 and then covered by the upper mold section 62. See Figure 5.

  The nozzle is attached to one end of the seamless sleeve, the necessary air pressure is formed in the sleeve, and carbon is formed in the mold hole 59 at the curing temperature. The curing temperature is usually 130 ° C. The other end of the seamless sleeve may be sealed, but depending on the air passing through one end, spraying takes place in the mold and the opposite end of the seamless sleeve is the sleeve 2 in the single tubular part of the mold. It may be sealed by bridging the two ends together.

  The graphite composite is cooled after being cured. The racket is then finished, including removing excess material, sanding and removing the handle base or racket shaft, eg, cutting.

  Thus, it is understood that the bottom of the shaft is hollow in the open state. Moreover, in order to implement the conventional manufacturing method, it is necessary to inject air into a carbon tube during heating. Thus, the racket obtained in this process will have an open end shaft.

In a preferred embodiment, a material with plastic hollow microspheres is used for foamed plastic formation. Microspheres are particles formed in a spherical shape and have a thermoplastic shell that covers the gas. When the microsphere is heated, the thermoplastic shell softens and the gas pressure increases. As a result, sphere expansion occurs. Microspheres or microcapsules containing blowing agents are about 10-30 μm in diameter, 5-15 μm thick, and 1.03 g / cm ³ in density.

  In a preferred embodiment, the curing temperature of the resin is about 150-150 ° C. The racket frame or other composite part is held at this temperature for about 20-35 minutes.

  The expansion ratio of the foamed plastic material selected in the present invention (Expancel 152) appears to be about 60: 1. In the present invention, the microcapsule foam-forming material used begins to expand from about 105-115 ° C. or higher. Expansion continues until the temperature drops to about 105 ° C. However, the aforementioned temperatures vary depending on the particulate foamed plastic product used. The major factor here is the nature of the resin used, the foaming agent, and the microcapsules.

  Thus, the microcapsules do not substantially begin to expand until the temperature approaches that required for curing and the melting temperature of the graphite fiber composite. It is understood that the capsule shell is composed of an acrylic copolymer resin. After expansion, the shell material forms the final foam core material of the graphite racquet. Alternatively, additional materials such as graphite whiskers may be introduced in powder form and mixed with the microcapsule powder to develop different properties. The blowing agent may be pentane or any other blowing agent suitable for the construction and application of microcapsules, such as a tennis racket frame.

  In the present invention, a particular foamed plastic material installed in the layup is Expancel 152, which is commercially available from Akzo Noble. A predetermined amount of Expancel 152 is placed in the seamless tube and the layup is wound so that the material is evenly distributed.

  The opposite end of the filling layup is sealed, for example by tying the end of the seamless tube, on which a resin-impregnated carbon fiber strip is wound. The filling layup is then formed in the shape of a rough product, such as a tennis racket, and placed in the mold hole at the bottom of the mold. The top of the mold has similar or substantially equal holes and the layup is carefully placed in the holes. The mold surface adjacent to the hole avoids layup biting.

  Thereafter, the mold is heated. When the desired temperature is reached, the microcapsules soften and the blowing agent dimensions for Expancel 152 expand. Upon cooling, the volume is substantially maintained in the expanded microcapsules forming the foamed plastic core at this stage.

  Therefore, the present invention simply requires the steps of placing the powdered polymer bead containing the foaming agent in the layup, sealing the layup, placing the layup in the mold, and heating to the desired temperature. Become.

  It should be noted that the present invention operates on microspheres that maintain physical sealing properties after heating, and microspheres that are open, fragile, physically collapsed, or deteriorate upon heating. is there.

  In principle, it is also possible to add other polymer materials, such as fine plastic powder or other suitable materials, to the Expancel 152 to change the properties of the blowing agent that is filled inside the final racket.

  This can be understood more clearly by referring to FIG. FIG. 6 shows a tubular seamless sleeve 40 covered with carbon fiber layers 42 and 44 and filled with Expancel 152 microcapsules 21. Instead of manual work, the sleeve 40 is closed using a mechanical process, for example by tying the ends of the seamless sleeve, or using clamps or staples, or by heat sealing.

  FIG. 7 schematically shows an aspect of manufacturing a layup tube 33 covered with fibers made of, for example, graphite soft fibers. This is formed from an open-ended, eg, transparent, tubular seamless sleeve shell 40 covered with a multilayer sheet of resin-impregnated carbon fibers. In principle, glass fibers or graphite fibers impregnated with resin may be used. For example, six different fiber layers 21-27 are separate fibers (or the same fiber). For example, the layers 22, 24, 26 have different properties and / or have different resins and / or different orientations. These layers form a soft unheated carbon tube layup 33.

  As shown in FIG. 8, a hermetically sealed soft fiber tubular layup 33 comprising microcapsules in the core sleeve 40 is fitted into the recess 43 of the bottom mold section 61. The core sleeve 40 is sealed at both ends. The sleeve 40 is curved into the general shape of a racket disposed in the recess 43 in the bottom mold section 61 of the mold 60. This is done manually or machine.

  As shown in FIG. 9a, in the processing of the lay-up 33 prior to thermoforming, it is important that the appropriate amount of microcapsules 21 is contained in the finished tube 10. The intermediate layer film or core sleeve 40 is preferably disposed between the first fiber layer of the layup 33 and the microcapsule 21. After expansion by applying heat to form the foamed plastic 30 (FIG. 9b), the core sleeve 40 functions to effectively prevent the microcapsules 21 from leaking during mold heating and fiber solidification. . This also prevents overflow, which maintains air pressure and adversely affects the quality of the finished product. In a preferred embodiment of the present invention, Expand-cell-l52A is used and the microencapsulated foamed plastic is processed at an intermediate temperature. Further, it is considered that a substantially uniform distribution of Expan-cell-l52A can be obtained over the entire length of the tube. For example, excellent results are obtained by tube rotation and tilting.

  As described above, the layup 33 is made of a flat graphite racket composite material and may be sealed. This may be done by twisting and tying the ends of the core sleeve 40, or simply by mechanically folding and compressing the ends of the tube. Alternatively, a mechanical device such as a small clip may be used. The clip is composed of, for example, a graphite fiber-containing plastic material that melts and becomes part of the final racket. Alternatively, a relatively small amount of adhesive may be used, such as a plastic softened by dope through a solvent such as acetone. If necessary, the dope is formed using a material that dissolves the plastic used for the dope and that does not dissolve the thermoplastic / graphite fiber composite. In yet another method, a thermoplastic material solvent containing graphite fibers is used.

  There are many ways to disperse the microcapsules in the finished filled fiber tube 10. For example, a transparent plastic tube having microcapsules is preformed and then stretched into a lay-up shape. Alternatively, the prefilled tube is covered with fibers to form the finished fiber tube 10. The second method is a method of injecting, injecting, or arranging the microcapsule into the fiber tube after being wound using a spare rod or core. The reserve rod or core is moved from the fiber tube. The third method is to use these methods to form second and third filling tubes and the like in the tube using the microcapsule-containing fiber tube.

  The mold is heated at 130 ° C. for the time for the carbon fibers to solidify. The curing time is preferably between 20 and 35 minutes. The microcapsule 21 does not expand and does not form the foamed plastic 30 until the heat is stabilized at a temperature necessary for solidifying the fiber containing the resin. As shown in FIGS. 9a and 9b, as a result of being cured by the heating process, an internal pressure is generated from the inside of the fiber tube due to the thermal expansion of the microcapsules, and the microcapsules are raised with respect to the wall of the mold hole. Usually, observation of the microcapsule manufacturer's handling is required.

  In the present invention, the shells of the microcapsules are plastic, so that they expand when the microcapsules are heated to a suitable temperature. The microcapsules forming the core plastic continue to expand, so that pressure is applied to the core sleeve 40, which in turn applies pressure to the graphite material. At the same time, the heat applied to the mold, and further the heat applied to the microcapsules heats the graphite / polymer resin sheet and cures them. As the microcapsules expand, they stretch the sleeve 40 and the carbon fiber polymer sheet tube, which move to the inner wall of the mold and are pressed against the shape of the mold, and the layers of carbon fiber material are pressed against each other . As the plastic cures, the layers melt together and the multilayered layer becomes a single thick structure.

  10 and 11 show a second embodiment. In this example, the fiber tube is placed in a microcapsule or filled tube and heated to solidify into a multi-layer tube, providing additional strength and rigidity to the racket.

  Filling tubes 12 and 12 'with foam plastic and microencapsulated foaming agent to form two tubes and covering the two tubes with a third tube 16 is done before heating and foaming the plastic. It is necessary to keep in mind that it may be broken.

  Alternatively, the microencapsulated foam material may constitute the foamed plastic in two different forms. The individual tubes are formed as described above (optionally on the first and second tubular sleeves), and the resulting tennis racket handle is as described above (optionally on the third tubular sleeve). Ii) covered with a second layer 16 of thermoplastic carbon fiber sheet, after which the assembly is heated twice at low temperature. At the high temperature of the first racket forming step, microcapsules designed to foam at high temperatures are used. Other microcapsules foam at a lower temperature, allowing a second heat and pressure to be applied during the formation of the tennis racket.

  It should also be noted that it is possible to form an entire tennis racket with double tubes. In this case, an internal structure composed of two tubes, usually in a sealed form, is obtained, for example, the internal structure has a flat wall that divides it into two and provides a certain strength.

  In the present invention, it is conceivable that the flat wall is perpendicular to the plane of the racket, as shown in FIG. However, the flat wall may be parallel to the plane of the racket depending on the play characteristics desired by the player. In this regard, it should be noted that the present invention can be used for products other than sports rackets, such as bicycles. For different parts of the bicycle, different configurations of the dividing wall extending along the entire length of the tube may be desirable. In products other than sports equipment, for example, there are baseball bats, and in this case, it is beneficial to have a plurality of dividing walls extending perpendicular to each other. This is significant when using four individual tubular compartments.

  In the present invention, it may be desirable to include five or more layups in a single structural member.

  In yet another example of a tube covering two other tubes, the other two tubes are filled with plastic and a microencapsulated foaming agent placed between the outside of the two inner tubes and the inner wall of the outer tube . The entire assembly is heated, the microcapsules foam, and pressure and foam plastic are formed. In this alternative, the microcapsules filled with foaming agent are placed between the outside of the two already formed inner tubes and the inside of the outer tube, the foaming occurs at low temperature and constitutes the foamed plastic at low temperature In the material, the heat will not be so high that the plastic formed during the first part of the manufacturing process remelts.

  Finally, foaming takes place simultaneously both inside the two small tubes and inside the cladding tube.

  The fiber tubes 12, 12 'may be wound manually or mechanically. Thereafter, another filled fiber tube 16 is formed. Finally, microcapsules are placed in both fiber tubes and tubes are obtained inside the tubes, or groups of tubes are obtained in a prefabrication process. In this spare pipe system, a plurality of walls can be formed in one outer pipe.

  Because of the additional support within the finished graphite composite part, the performance and properties of many finished products are substantially increased by performing such a two-step process or by a group of fiber tubes.

  It should be understood that such multiple tubes are only one example of the present invention. It is understood that the present invention may be implemented with a single tube structure or a hybrid structure with multiple and single tube portions, such as the tennis racket described above. Also, the multiple tube or hybrid structure is particularly important in applications where relatively high demands are made, such as bicycle frames and automobile body parts. In particular, in the present invention, the graphite fiber composite member has a two-dimensional arrangement such as a tennis racket and a bicycle frame, as well as a configuration in which the axis of the component extends three-dimensionally, such as a chair, a car cabin, or a tractor type lawn mower. It is conceivable to configure the machine frame.

  As is clear from the above description, in the multiple tube process, various shapes of configurations can be made without using a mold, and these can be formed by using, for example, a mold preformed on the outer tube. Or it is the graphite fiber composite material pipe | tube comprised without using, and functions as a hole wall instead of a mold. This is conveyed to the furnace using a conveyor belt and heat cured without the use of a mold. This results in high production efficiency and low operating costs. In this embodiment, the initial tube set or other mold need not give the layup the same strength as a conventional iron mold, but simply required to form a high strength graphite composite according to the present invention. It will be appreciated that there may be strength against pressure. This embodiment is completely machine-implemented and human power is minimized or unnecessary.

  In FIG. 12a, the mold 40 is shown. In this case, the handle portion 41 of the racket 10a is disposed for further hardening, and the second handle reinforcing member 30 is formed in the void space 11 defined by the frame 20.

  FIG. 12b shows a cross section of another example of the tube structure 30 in the tube 20. FIG.

  FIG. 13 shows an example of a mold 60 that defines a hole 21 for manufacturing the head 18 that is used for molding into a separate second frame.

  FIG. 14 shows the structure of a badminton racket having a head portion 10, a foam plastic pressing material 30, and a T-type support member 72 that receives an end portion 73 of the head 10. The central support member 71 of the T-shaped support member 72 is received in the handle member 20. The handle member 20 including the end portion and the handle portion 10 are defined by carbon fiber layup, and are firmly disposed around the T-type support member 72.

  Figures 15 and 16 show yet another embodiment of the present invention where a racket weight distribution is required. Within the arrangement, a racquet weight distribution balance weight 50 is added, which becomes the fiber composite tube 10 prior to the solidification and curing process of applying heat to the microcapsules 30. This is difficult or impossible with conventional air injection techniques. This is because the weight hinders the coupling of pressure to the racket portion. The weight is composed of various materials, and may be rubber, silicon, plastic, metal, or other materials.

  In the present invention, the amount of foam plastic material is selected to fill the desired volume and provide the desired pressure. Other factors are the amount of weight when foam contributes to the structure, and the structural properties of the whole part after the foam core is formed. The multiple tubes may be of substantially equal volume, assuming that the heat, mold volume, and amount of foamed plastic microcapsules are uniform. Since the mold holes are heated uniformly, the mold is expected to heat the layup uniformly.

  The need for racket weight and balance is well known in the art. To date, however, these weights have been added only after solidification of the graphite fiber composite. In a third embodiment, a weight can be added to the racquet head itself during the manufacturing process, for example by arrangement of the sleeve 40 (FIG. 6) or by arrangement within the mold hole. Alternatively, receiving weights may be incorporated during the manufacturing process. The advantage of doing this during the manufacturing process is consistency and ease, for example, because of the balance of the racket head, a weight structure is added during mass production, making post-manufacturing customization easy. is there.

  Further, in this embodiment, since air cannot pass through the object in the pipe, it is possible to form a plurality of structures that is impossible with the prior art.

  FIG. 17 shows an exploded plan view of the customized racket 14 after completion. In the figure, a handle portion 15, head weight strips 25a and 25b capable of holding weights, a handle portion 14a, and handle weights 16a, 16b and 16c are shown. Alternative handle portions 14b, 14c are shown. The handle weights 16a, 16b, and 169c may be 2g, 5g, and 10g, respectively. The butt cups 5b and 5c are customizable and interchangeable.

  The racket 12 with interchangeable handles 14, different weights 16, different butt cups 5, and different head weights 25 of different shapes and dimensions allows the user to form the desired weight, balance, and exact custom parts Can do.

  The main concept of the method of the present invention is that instead of the conventional method using compressed air, the pressure of a microencapsulated foamed plastic, such as Expancel152, is used to place high pressure in the layup fiber tube. And forming the layup into a thermosetting shape corresponding to the mold hole wall. The system of the present invention has many advantages. First, the manufacturing method of the present invention using a thermosetting and foaming process in one step simplifies the manufacturing process and increases the efficiency of the manufacturing operation.

  Second, the manufacturing method of the present invention uses foamed plastic pressure, such as that produced by microcapsules, thus avoiding air leakage and avoiding obscure manufacturing parameters when using air. Can do. This has the effect of reducing the manufacturing defect rate.

  Third, the method of the present invention provides a completely new method for introducing a weight that does not require drilling, and can be placed directly on an internal frame attached to the head, for example.

  In the present invention, there is no air pipe that is manually attached, and the racket can be fully automated. The present invention includes: a) filling a microcapsule into a sleeve, b) impregnating graphite fiber with resin, c) wrapping the graphite around the sleeve, d) bending the graphite fiber to make the lay-up the desired shape, e A series of manufacturing steps including :) placing the bent layup into the mold; f) heating the mold; g) cooling the mold; h) opening the mold and removing the finished racket frame. Does not include human power.

  In the present invention, a gut hole may optionally be formed during the formation of the racket frame. The holes may be obtained by forming them in the racket head. Alternatively, a half layup pair is used to form the head of the racket frame, extend across the mold hole, and half by a metal post supported in a slot provided in one or both of the half molds. A hole may be formed between them.

  Referring to FIG. 18, this figure shows in detail the production of the present invention of a graphite composite member, for example a sports racquet frame such as a badminton racquet frame. In particular, the sports racquet may be manufactured by the production of the first graphite fiber using Torayca's graphite fiber from Toray, which has many different aspects. From the viewpoint of the rigidity of the frame formed using this material, ToraycaT1000GB incorporating 12000 graphite filaments into flat ribbons of fibers aligned in the axial direction is considered to be suitable as a frame for tennis or badminton rackets. . However, if the final racket requires flexibility, ToraycaT700SC may be used. In any of these products, the graphite takes the form of a ribbon in which thousands of fibers are stretched laterally. Since it is provided in the form of a ribbon, handling by mechanical processing as described below is facilitated.

  The graphite fiber ribbon 100 containing ToraycaT1000GB is opened from the spool 102 and guided to the bat 106 by the rotary mounting rod 104. The bat 106 has a liquid resin 108. The resin 108 is of a type that is cured by application of sufficient heat. In the preferred embodiment of the present invention, the liquid resin 108 is a thermoset epoxy resin, which is sold under the name WH-2370A by Wah Hong Industrial Corporation of Kaoh Siung, Taiwan. The fiber ribbon 100 is guided toward the liquid resin 108 by the rotating mounting rod 110. The liquid resin 108 passes through the ribbon 100 at a speed of about 1 to 2 m / second, and the liquid resin is impregnated in the space between the fibers constituting the graphite fiber ribbon 100.

  Next, the impregnated ribbon is also fed around the rotating mounting rod 112. The impregnated ribbon 114 is wound on a release paper layer 116 attached to the surface of the rotary mounting drum 118. In the preferred embodiment, ribbon 114 is wound around drum 118 to form coils 120 that slightly overlap each other.

  In the case of manufacturing a conventional tennis racket, the graphite fibers constituting the racket are oriented in various directions. Thus, the coil 120 having a generally cylindrical structure is cut at different angles, for example, along a line perpendicular to the tangential direction oriented perpendicular to the axis of the drum 118. Cutting with such a line is facilitated by a groove on the drum oriented in the appropriate direction, as described above, ie a groove that receives the tip of a blade that cuts graphite fibers. Various angles are selected to facilitate the assembly of a flat layer of flat material formed by the coil 120. For example, when manufacturing three graphite flats used in the assembly of a layup, if one layer of fiber is oriented horizontally and the other two layers of fiber are oriented at ± 19 °, By using a second groove properly oriented on the outer surface, it is facilitated to cut the fibers in the desired 19 ° orientation.

  To produce a two-layer graphite fiber flat member, each having a different orientation, simply use one graphite flat member with back sheet 116 and exposed graphite fiber layer 120 manufactured using the process described above. Then, this may be disposed on the graphite fiber left on another release member in an appropriate orientation. It is preferred to use graphite impregnated with resin and supported on a single release sheet, after which the release sheet is removed for each handling. Of course, two flat graphite members having the same orientation may be placed at a desired angle relative to each other and cut if necessary. If three layers are required, one of the back sheets 116 is removed and another graphite flat member is placed on the two-layer assembly with the exposed graphite fiber layer 120 in contact with the graphite fiber layer 120 of the assembly. Is done.

  It should be noted that in standard manufacturing of graphite rackets, multiple layers need to be oriented in different directions to give strength to the final frame structure. The present invention may be applied to any conventional graphite assembly structure, and the racket having excellent athletic characteristics can be obtained by adjusting the orientation, the total length, the width, and the like. However, with the technique and method of the present invention, the processor can reduce the cross-section, suppress the effect of wind resistance, and reduce the weight of the racket. The width of the element forming the hoop of the racket frame is narrowed, and in the cross section of the hoop part of the frame (in the case of a tennis racket), the thickness and / or width is smaller than between 2 mm and 5 mm, but high In tension, a sufficiently high strength can be obtained against the racket gut.

  In FIG. 19, a multilayer graphite fiber structure 122 is shown. If desired, this may be oriented by cutting the strip 24 as shown in FIG. 21, as shown in FIG. Similarly, as shown in FIG. 22, the fibers may be oriented at a relatively acute angle with respect to each other. As a result, as shown in FIG. 23, processing of the strip from the material becomes possible.

  The badminton racket of the present invention may be constructed using the following process. Typically, the dimensions and fiber orientation of each strip of resin-impregnated graphite fibers used in the present invention for producing a graphite composite frame are the same as those used in the production of conventional graphite frames, but the width Decrease. This is because the thickness of the racket in the direction perpendicular to the head surface of the racket is reduced by, for example, 2 or 3 mm, but at least sufficient strength is obtained. Further, according to the present invention, the thickness of the frame in the surface direction of the head can be reduced, and such a preferable configuration has an effect of suppressing wind resistance against the movement of the racket.

  The plurality of resin-impregnated graphite material strips 126 shown in FIG. 24 have dimensions of 29 cm × 6 cm. The total length is 29 cm, which is selected to substantially align with the circumference of the badminton racket head to be manufactured. As schematically shown in FIG. 25, the strip 126 has a layer that is ± 19 ° relative to the total length of the strip 126. As shown in FIG. 26, the second strip 127 is substantially equal to the strip 126 and is disposed on the strip 126. Thereafter, a narrow strip 128 with graphite fibers oriented perpendicular to the entire length of the strip is placed on the two strips, and the entire upper length of the strips 126-128 is substantially as shown in FIG. Aligned. Thereafter, for example, a keystone-like piece 130 having two layers, oriented at ± 30 °, is added to provide additional strength and allow the gut to be placed in tensile strength. In general, since the resin is relatively tacky, even in the uncured state, the assembly 132 of the strips 126-130 is somewhat bonded, and therefore handling of the assembly is relatively easy.

  In the preferred embodiment of the present invention, winding is performed using two core portions having core portions 134 and 136. The core portions 134 and 136 are disposed in the tubular nylon sleeve 138 as shown in FIG. The sleeve 138 has a characteristic that it does not melt when heat is applied. Thus, when placed on top of the core portions 134, 136, it is sized somewhat larger, as shown by the thin lines in FIG. As indicated by the bold lines in FIG. 29, the excess portion of the sleeve is folded over the length of the double stick tape to just contain the core portion firmly. Also, the excess portion of the sleeve serves to accommodate the expansion of the sleeve when it is pressed against the layer of resin-impregnated graphite fiber. During this process, the resin layers may slide relative to each other.

  The core portions 134 and 136 have a width of about 8 mm and a thickness of about 1.5 mm, and are made of steel, for example. The core is provided in two core parts 134, 136, allowing for easy removal of the core from the layup with minimal interference with the wound layup, as detailed below. Become.

  Next, the assembly 132 is wound around the nylon sleeve 138 on the core portions 134 and 136 by, for example, a rolling method as shown in FIG. The rolling method is continued as shown in FIG. Before the rolling is complete, a set of end strips 142 shown in FIG. 32 (in the typical example of the prior art, the fibers are arranged in a number of layers oriented at an angle with respect to the total length); A full length strip 144 (conventional full length, width, fiber orientation, and number of layers) shown in FIG. 33 is disposed on the assembly 132 as shown in FIG. Thereafter, the rolling is continued until the graphite layer is wound around the core as shown in FIG. The end strip 142 has graphite fibers oriented parallel to the entire length, whereas the full length strip 144 is composed of graphite fibers oriented perpendicular to the entire length of the strip. The overall length, width, fiber orientation, and number of fiber layers are known in the art and are not part of the present invention.

  Next, an additional layer of graphite strip is rolled to complete the layup. In particular, another set of end strips, for example with orientation and dimensions equal to end strip 142, and another full length strip identical to strip 144 are placed on the assembly shown in FIG. Next, a final wound sheet of two layers of graphite fibers having fibers oriented at ± 30 ° and having a width of about 4.5 to 7 cm is covered on the assembly shown in FIG. 35 and shown in FIG. An assembly is obtained.

  When the layup as shown in FIG. 36 is completed, it is pulled from the layup to remove the core portion 134 from the layup, but the opposite end of the nylon sleeve 138 is gripped by the other portion. . The opposite movement removes the core portion 136 from the layup, leaving the inside of the sleeve 138 open.

  Next, 1 g of Expancel 152 represented by reference numeral 146 is placed in the cylindrical half spoon portion 148 of the spoon 150 (FIG. 37). The foamed plastic forming material 146 is uniformly spread over the entire length of the spoon portion 148. Spoon portion 148 has a length equal to approximately half the length of nylon sleeve 138. Next, the spoon portion 148 is inserted into the layup 152 (FIG. 36). The spoon 150 is then rotated in the axial direction, releasing the foamed plastic forming material 146 along the half of the layup 152, which is distributed substantially uniformly. The process is then repeated with another 1 g of Expancel 152 and the other half of layup 152 is filled.

  Thereafter, the end of the nylon sleeve 138 is sealed, and the layup is manually rotated and rolled, resulting in a more uniform distribution of the foamed plastic forming material 146. Next, the layup 152 is wound around a wooden mold (FIG. 38) to form a generally badminton racket frame shape. Referring again to FIG. 39, the tubular member 156, which is a graphite composite or other material, is then cut to form a slot 158 that receives the glued crosspiece 160 as shown. The parts are then placed as in FIG.

  Next, as shown in FIG. 41, the end of the layup 152 is pressed against the end of the cross piece 160 from the direction of the arrow 162. Next, strips 164, 166, 168, each having a total length of 10 cm and a width of 1.5 cm, are placed on the frame member to provide a coupling function in their proper positions. The strips 164, 166, 168 may all be two-layer graphite members, with one layer aligned at + 45 ° to the total length and the other layer being −45 to the total length of the strip. Aligned.

  Next, an additional strip 170-184 is applied to the badminton frame layup, as schematically shown in FIGS.

  The strip 170 is applied in a u-shape as shown in FIG. The strip 172 is wound around the head from the left side, passes through the center, and is wound around the right side of the head. The strip 174 is coiled around the handle of the racket frame. The strip 176 is shaped like a barbell. The strip 176 is centered at the junction between the handle and the head or hoop, and then spirally wound on both sides of the adjacent elliptical head in tension. Referring to FIG. 46, an elongated diamond-shaped patch 178 is passed through the head, the patch 178 is centered on the handle, and both ends of the patch 178 are wound around the handle and come into contact with the handle. Next, an elongated parallelogram patch 180 is placed over the diamond patch 178 and pressed against the handle and other parts of the racket.

  It should be noted that typically all coverings of resin-impregnated graphite fiber patches are made without gaps and are approximately compatible with existing assemblies of the frame structure. This is facilitated by the viscosity of the resin saturated graphite fiber patch. As shown in FIG. 48, the second parallelogram patch 182 is disposed on the first parallelogram patch 180. As shown in FIG. 49, the patches 184, 186 are then attached to the outside of the arcuate portion of the half racket.

  As shown in FIG. 50, the layup of the badminton racket frame is disposed in the hole 188 in the mold bottom 190. Next, the corresponding upper part of the mold is placed on the mold bottom 190. Care must be taken not to pinch the graphite fibers. This is done by receiving and placing the layup in the hole 188. The assembly is then heated to cure the resin. Heating may be performed by placing the mold in an oven or by circulating a high-temperature liquid such as water or oil in a groove provided in the mold. In order to cure the graphite / resin member constituting the layup, the layup needs to be heated with an error of about 145 ° C. ± 5 ° C. However, this temperature depends on the particular foamed plastic forming material used, and a good frame is produced by the temperature at which the foaming, curing and expansion of the plastic is obtained, and sufficient pressure.

  Heating continues for about 25 minutes, but longer durations do not adversely affect the final product. As a result of the application of heat, pressure is created on the layup graphite layer, creating a strong structure, possibly creating some displacement relative to the other layers during this process.

  When the heating is completed, the mold is preferably cooled by circulating cooling water through a passage provided in the mold for heating and cooling, for example. This is necessary to fully cure the foamed plastic material formed with Expancel 152. This avoids further expansion of the frame material that may occur when removing the racket frame from the mold. It has been found that cooling to 10-15 ° C produces a frame with excellent properties. However, this particular temperature range is not as important. The racket is then finished in a conventional manner, drilled, gutted, and applied with a suitable handle grip.

  In principle, the mating mold halves have heating and cooling passages, but the mold need not have such passages arranged between a set of metal plates having such passages. This may be used in receiving hot and cold liquids that heat and cool a clamshell mold having two parts secured between metal plates.

  Hereinafter, the production of tennis rackets will be described. The frame is constructed using a nylon tube fixed around the core using double stick tape as described above. The process steps for manufacturing a tennis racket frame are similar to those for manufacturing a badminton racket, except that the amount of carbon fiber and foamed plastic is substantially high.

  As shown in FIG. 51, in the manufacturing method of the present invention for a tennis racket using many graphite fiber strips, when formed into a racket, the layup 210 is removed from the base of the racket handle as shown in FIG. Stretch through the full length of the handle, go around the circumference of the racket head and return to the base of the racket handle along the full length of the handle. The throat is formed with a cross piece 212 that ends around the head of the racket. Although the crosspiece 212 may be manufactured using the process of the present invention, this property is not critical. This is because it is well supported and has a short overall length. The crosspiece 212 is supported by a spirally wound side path, or by other graphite resin fiber strips, as in the badminton racket manufacturing process described above. After the layup is formed, it is shaped into a normal tennis racket that is formed around a wooden mold. Next, the cross piece 212 is fixed to the above-described resin-impregnated carbon fiber strip. The fiber structure is then completed by covering the handle with several layers of graphite fibers having different orientations, giving strength in all directions.

  Referring to FIG. 51, a schematic exploded plan view of a plurality of parts of a tennis frame is shown. In FIG. 51, the portion of the crosspiece that defines the throat of the tennis racket frame is not shown, but the configuration of the crosspiece is shown after the description of the arrangement of FIG. It should be noted that in this exploded view, the same parts are shown only once in some cases, as will become apparent below.

  After the sleeve is wound and secured around the twisted core, a first strip 216 having a length of 155 cm is centered over the nylon sleeve and tightly wound. The strip 216 has two layers of graphite fibers that are oriented at + 30 ° and -30 ° with respect to the overall length. The strip has a width of 7.2 cm. The various strips of graphite / resin material are covered in turn with a nylon sleeve that covers the core, as shown below. Next, strips 218, 220 are placed 74 cm from the centerline 222 of the layup. The strips 218, 220 are trapezoidal and have two layers of graphite fibers. One is + 30 ° to the total length of the strip and the other is -30 °. After the strips 218, 220 are placed, a second set of strips (7.2 cm wide, 11 cm long, 9 cm short) equal to the strips 218, 220 are placed. Optionally, as shown, these may be arranged in an upside down orientation. These strips are placed on what is outside the frame.

  It will be appreciated that FIG. 51 shows the distances from the layup centerline 222 to the various ends of the carbon fiber strip. That is, strip 216 is located at the center of the layup, has a total length of 155 cm, and is 77.5 cm from centerline 222 to each end. Similarly, the strip 218 has an overall length of 11 cm, a short length of 9 cm, and is disposed at a distance of 74 cm from the center line 222. The distances from the centerline of the layup to the various ends and corners of the strip are shown in cm in FIG.

  The strip 224 has a trapezoidal shape, and extends from a position (left side) 82 cm to the center line 222 to a position (right side) 5 cm from the center line 222. The strip 226 is a mirror image of the strip 224. The strip 226 has a trapezoidal shape, and extends from a position (right side) of 82 cm to the center line 222 to a position (left side) of 5 cm from the center line 222. The strips 224, 226 are 87 cm long and have two layers of graphite fiber strips, each layer extending at + 10 ° and −10 ° relative to the total length of the strip. After the strips 224, 226 are placed, a similar set of strips is placed on top.

  A strip 228 having a total length of 130 cm is composed of two-layer graphite fibers, each layer having a + 30 ° and −30 ° slope relative to the total length. Such strips are installed twice and, if necessary, are placed upside down during the second installation. Unlike the strips 216-226, the strip 228 may be placed inside the racket frame. The strips 224, 226, 228 all have a width of 7.2 cm.

  A strip 230 having a total length of 92 cm and a width of 2 cm is disposed outside the racket head and has fibers extending transversely to the total length of the strip 230. It should be noted that when the graphite fiber strips are installed, they are processed while attached to the release paper (preferably all graphite fiber strips are used in the method of the invention). This is particularly important for the strip 230. When these are installed in the layup, the release paper is peeled off.

  A strip 232 having a width of 0.5 cm has two layers with fibers parallel to the entire length. This is covered outside the racket layup. The strip 232 is disposed on the portion that becomes the surface of the layup racket. A second strip, the same as the strip 232, is placed on the opposite side of the racket.

  A strip 234, 2 cm wide and 12 cm long, has two layers of graphite fibers. One layer has fibers parallel to the entire length of the strip and the other has fibers perpendicular to the entire length of the strip. When the first strip 234 is placed inside the layup, the second identical strip 234 is placed outside the layup.

  The strip 236 has a width of 3 cm and is composed of two layers, each layer having graphite oriented at + 10 ° and −10 ° with respect to the total length of the strip. After the first set of strips 236 is placed outside the layup, the second set of strips 236 is placed inside the layup.

  The strip 238 has a width of 2 cm and a total length of 90 cm and is arranged inside the layup. The strip 240 has a width of 7.5 cm and is placed inside the layup. The strip 240 is a two-layer structure, with each layer oriented at + 30 ° and −30 ° with respect to the overall length. Two strips 240 are placed inside the layup.

  The strip 242 has a width of 7.9 cm and a total length of 122 cm and is composed of two layers with fibers oriented at + 10 ° and −10 ° with respect to the total length of the strip 242. Two such strips 242 are placed outside the layup.

  The strip 244 has a total length of 155 cm and a width of 8 cm and is a two-layer structure, each layer having graphite fibers oriented at + 30 ° and −30 ° with respect to the total length of the strip 244, respectively. Two such strips 244 are placed outside the layup.

  Each strip 246 has a width of 7.5 cm and a total length of 11 cm. The strip 246 is a two-layer structure and the fibers are oriented at + 30 ° and -30 ° with respect to the total length of the strip. Four sets of such strips 246 are wrapped around the outside of the layup.

  The strip 248 has a width of 2 cm and a total length of 10 cm, and has a two-layer structure with the fibers oriented at + 10 ° and −10 °. Two such strips 248 are placed inside the layup. Similar to other trapezoidal and parallelogram shaped strips, the second set of strips may be structurally symmetric as shown in the figure from top to bottom. Two such strips 248 are used.

  The strip 250 has a width of 3 cm, has a four-layer structure, and the graphite layer is oriented at + 10 ° -10 °, + 30 °, and -30 °.

  In this regard, any structure constructed using a conventional air compression system that uses an external air pressure source can be used in the method of the present invention as well, and can be adapted to reduce material requirements. You need to keep in mind that you can.

  After the main part of the frame layup has been completed using the strip shown in FIG. 51, 25 g of Expancel 152 is installed on the nylon sleeve, on which the graphite / resin strip is wound. This is done twice, with 12.5g each inserted into each half of the layup corresponding to the core, covering the layup. After the introduction of Expancel 152, the end of the nylon sleeve is tied or sealed so that pressure is maintained during foaming of the plastic core.

  Next, the lay-up cross piece 212 is configured by firmly winding a tubular nylon member around the core with a normal double stick tape such as that used for office work. As in the previous badminton racket example, various strips of graphite / resin material are used, which are wrapped around a nylon sleeve covering two cores.

  First, a first strip having a width of 6 cm and a total length of 12 cm is wound around a nylon sleeve. The fibers are oriented at + 30 ° and -30 ° with respect to the total length of the strip. Next, another strip of fibers with an overall length of 11 cm and a width of 11 cm and oriented at + 10 ° and −10 ° with respect to the total length of the strip is used. Next, a strip having a width of 21 cm and a width of 11 cm, with ends tapered about a distance of about 2.5 cm, and fibers oriented at + 30 ° and −30 ° with respect to the total length. , Wrapped around the previous layer.

  Next, another strip is added to the assembly with two layers having a total length of 10 cm and a width of 2 cm, with fibers oriented at + 10 ° and −10 ° relative to the total length of the strip. This strip is wound around the portion of the racket head that is inside.

  Next, another strip is added to the assembly, having a total length of 10 cm, a width of 2 cm and having two layers with fibers oriented at 90 ° and 0 ° with respect to the total length of the strip. This strip is centered at the outer part of the racket head and wrapped around it.

  Next, a strip with fibers oriented at + 30 ° and -30 ° with respect to the full length, 21 cm long, 4.5 cm wide and tapered at a distance of about 2 cm at the end is the previous layer Wrapped around. A strip having a length of 10 cm and a width of 7 cm with fibers oriented at + 30 ° and −30 ° with respect to the total length is then wound around the previous layer.

  After the layup of the crosspiece 212 is formed and the core is removed, 2 g of Expancel 152 is introduced into the nylon sleeve, on which the layup of the crosspiece 212 is wound. The end of the nylon sleeve is sealed, preferably by providing a knot in the tube defined by the graphite layer of the crosspiece layup. This completes the formation of the layup. If necessary, the step of tying the end of the nylon sleeve may be omitted in the crosspiece layup, and pressure is applied by the pressure from the mold and the adjacent portion of the main layup head (foam expansion) The ends of the crosspiece layup are sealed during heating and curing.

  As shown in FIG. 52, the layup 214 includes a cross piece 212 and a main frame portion 210. These are made into the desired shape using wooden foam before receiving additional strips and resin impregnated glass fiber patches, as shown in FIG. 53, and placed in an iron mold bottom member 216, as shown in FIG. It is done. The wooden foam has a head support 218 and a throat support 220. Thereafter, additional strips and patches are added to the layup, as shown below. The completed layup is then placed in the iron mold bottom member 216 as shown in FIG.

  Referring to FIG. 55, the tied end of the nylon sleeve with knot 218 may pop out of the iron mold. Alternatively, as shown in FIG. 56, the knot 222 is pushed in during the filling layup, and the mold is configured to form a flat bottom, in this case, as shown in the embodiment of FIG. The need to cut at the base is eliminated.

  Referring to FIG. 57, the process of attaching the cross piece 212 by covering the aforementioned additional strips and patches will be better understood.

  In particular, referring to FIG. 57, the crosspiece layup 224 receives a second tubular graphite / resin support member. This second tubular graphite / resin support member is constructed by wrapping a resin-impregnated two-layer graphite strip into a tube, the strip having a total length of 10 cm and a width of 21 cm, with a tapered end. And the layer is oriented at + 30 ° and -30 ° with respect to the total length of the strip. The tube will have a diameter when the support member 226 is flattened, and the width should be slightly less than the thickness of the completed racket frame.

  This second tubular graphite / resin support member is constructed by wrapping two layers of resin-impregnated graphite strip around the tube, which is 10 cm long and 7 cm wide, and that layer is relative to the total length of the strip. Oriented at + 30 ° and -30 °. The tube will have a diameter when the support member 226 is flattened, and the width should be slightly less than the thickness of the completed racket frame.

  Another graphite / resin strip 228 is wrapped around the cross piece layup 224 and the support member 226. Strip 228 is a resin impregnated two-layer graphite strip having a total length of 10 cm and a width of 7 cm, each layer being oriented at + 30 ° and −30 ° with respect to the total length of the strip. As shown in FIG. 58, the strip 228 is wrapped around the center of the combination of the crosspiece layup 224 and the support member 226.

  After the cross piece layup 224 is constructed, it is placed and secured on the wooden foam of FIG. 53, along with the main part 210 of the racket frame. As shown in FIG. 59, the cross piece lay-up 224 and the ends 230, 232 of the support member 226 are each bent away from each other. The main part 210 and the combination of the crosspiece layup 224 and the support member 226 are then placed on the wooden foam of FIG. The relative position of the frame elements can be confirmed from FIG. 60, where the wooden foam is not shown for clarity. All four ends 230, 232 are then joined by a strip of graphite fiber impregnated with resin, the total length of which is about 12 cm and the width is about 1 cm. These are single layer graphite fiber strips, and the fibers may be oriented along the entire length of the strip. Some overlap is allowed, but by wrapping it in a smooth helix, a bond is made between the ends of the strip, generally indicated by helix 234 in FIG. The spiral is not shown at the other end, but they are wound similarly.

  The handle portion of the frame is wound by two strips of carbon fiber, each strip having a two-layer structure with the fibers oriented at + 30 ° and -30 ° with respect to the total length of the strip. Each strip has a total length of 17 cm and a width of 4 cm.

  The completed layup is then removed from the wooden foam, placed in the bottom half of the iron mold and heated. When a sealed handle iron mold as shown in FIG. 61 is used, tying the end of the nylon sleeve may be omitted to form the main part 210 of the layup. The end of the nylon sleeve is simply folded and placed between the two ends of the main part of the layup. Such a simple fold may optionally be performed on the end of the nylon sleeve of the crosspiece, which is in the tube formed by the graphite layer wound to form the crosspiece, It is pushed in carefully.

  In the present invention, the graphite composite member can also be manufactured without using any impermeable member such as a tubular nylon sleeve. In this case, the graphite strip is wrapped directly around the core, and perhaps the graphite strip has a first resin-impregnated graphite layer coated on one side with a release agent such as an inert powder, so that the layer is It is prevented from adhering to the core. The tubular layup may then be formed by continuous wrapping of additional graphite / resin strips. When the layup winding is complete, the completed layup may have ends that are folded over to overlap and may be substantially sealed. Next, for example, as shown in FIG. 56, for example, a tennis racket component is placed in a sealing mold. Further, before the layup is wound, for example, an open semi-cylindrical core having a configuration of a spoon 150 and including a plastic foam material (Expancel152) in the spoon portion 148 may be used. In addition, the spoon portion 148 is preferably formed to have a square or other shape cross section. When such a spoon core is used after the layup has been wound, only a rotation is required for the layup, which causes the plastic forming material to fall to the inner surface of the layup. The spoons are then removed and the ends are folded to seal them before placing them in the mold and heat curing as shown in FIG.

  Although an exemplary embodiment of the present invention has been described, it will be understood by those skilled in the art that various modifications of the method and materials used of the present invention will be apparent based on the foregoing description and description. In addition to these obvious changes, the present invention may be applied to other fields. For example, the technique of the present invention can be used to form a bicycle frame, where different orientations are applied to different parts of the frame, and in use, the stresses formed on these parts of the frame. I can deal with it. Such modifications are encompassed within the spirit and scope of the invention, which is limited only by the scope of the appended claims.

Claims (30)

A tubular member having first and second ends for use in manufacturing a sports racket frame,
The first and second ends are configured to substantially seal the interior of the tubular member;
The tubular member is composed of a first resin material and a plurality of fiber layers,
The tubular member is filled with a substantially sealed sleeve, the sleeve being filled with a second resin material containing a foaming agent. A resin and fiber assembly used in the manufacture of sports racket frames,
A substantially sealed sleeve;
A plurality of fibers having a first resin material in between, a plurality of fibers disposed on the sleeve;
A hole defined in the sleeve;
Have
An assembly in which the holes are filled with a second resin material containing a foaming agent. The tubular member according to claim 1,
The second resin material has a foamed plastic having open cells or closed cells,
The sleeve is a tubular member, which is an air-impermeable sleeve.   The tubular member or assembly according to any one of claims 1 to 3, wherein the plurality of layers of fibers have different orientations. The bore, the tubular member or assembly according to any one of claims 1 to 3, characterized in that it is a pressure of more than 20 lbs / inch ^2.   The tubular member according to claim 1 or 3, wherein at least one of the first and second ends is configured as a knot.   The tubular member according to claim 1 or 3, wherein the first and second end portions are configured as folds.   The tubular member or assembly according to any one of claims 1 to 3, wherein the first resin material disposed between the fibers is adapted to be cured by heat.   The tubular member or assembly according to any one of claims 1 to 3, wherein the second resin material is adapted to be cured by heat.   The tubular member or assembly according to claim 1 or 2, wherein the second resin material surrounds the foaming agent. The first resin material is cured by heat,
The tubular member or assembly according to claim 1 or 2, wherein the second resin material surrounds the foaming agent and expands at a temperature substantially equal to a curing temperature of the first resin material. The second resin material surrounds the foaming agent;
The tubular member or assembly according to claim 1 or 2, wherein the second resin material and the foaming agent are in a non-rigid form.   The tubular member or assembly according to claim 1 or 2, wherein the second resin material and the foaming agent are in a powder form.   The tubular member or assembly according to claim 1 or 2, wherein the second resin material and the foaming agent have an expansion ratio larger than 30.   The tubular member or assembly according to claim 1 or 2, wherein the second resin material and the blowing agent have an expansion ratio in the range of about 50-70. A method of manufacturing a sports racket frame,
(A) winding a flat member of a fiber impregnated with a resin material around a core and laying up;
(B) extracting the core to obtain the laid-up tubular member;
(C) disposing a foamed plastic forming material inside the tubular member;
(D) substantially sealing both ends of the tubular member to form an air bag;
(E) placing the sealed air bag in a mold;
(F) forming a foamed plastic from the foamed plastic forming material;
(G) curing the resin material;
In order. further,
The method of claim 16, further comprising: (h) removing the air bladder from the mold.   The method of claim 16, wherein the mold includes a member that forms a permanent part of the fiber composite member. further,
The method according to claim 16, further comprising the step of covering the core with a sleeve before winding the flat member.   The method of claim 19, wherein the sleeve is firmly fixed around the core by using an adhesive material.   20. A method as claimed in any one of claims 16 to 19, wherein the fibers comprise graphite fibers.   20. The method according to any one of claims 16 to 19, wherein the core comprises a set of two cores. The foamed plastic forming material foams under heating,
The method according to claim 16, wherein the resin material is cured by application of heat. The foamed plastic forming material forms a foamed plastic when exposed to a temperature sufficiently close to a temperature at which the resin material is cured by application of heat,
The method according to claim 16, wherein the foamed plastic pressurizes the flat member when the resin material is cured.   20. A method according to any one of claims 16 to 19, wherein the end of the bladder is sealed by tying.   20. A method according to any one of claims 16 to 19, wherein the end of the bladder is sealed by folding.   20. A method according to any one of claims 16 to 19, wherein the foamed plastic forming material forms a foamed plastic and generates a pressure greater than 30 psi. The foamed plastic forming material, the method according to any one of claims 16 to 19, characterized in that foamed plastic is formed to generate a pressure greater than 5 kg / cm ^2. The foamed plastic forming material, the method according to any one of claims 16 to 19, characterized in that foamed plastic is formed to generate a pressure greater than 15 kg / cm ^2. The method according to claim 16, wherein the step (a) includes the step of laying up a flat member of a fiber impregnated with a resin material by wrapping around a sleeve disposed around the core.

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